"This was a very serious, a very detailed report that was put forward by the House of Commons," she told the BBC.

"Ian has apologised to the House of Commons. He has apologised to his constituents and he has apologised personally to me in relation to his conduct.

"What happens now is that it is taken to the officers of the party and they will decide what course of action to take in relation to Ian."

Mr Paisley's twin Kyle, a Free Presbyterian minister in England, stood by his brother on social media.

When asked on Twitter about the controversy, Kyle Paisley challenged some of those criticising his brother.

"I have more issues with former terrorists calling for his political blood, who are never happier as when they see people fall; and with political opponents who view a man's fall as a season of opportunity, something to be grasped for one's advantage," he tweeted.

Calls for Mr Paisley to resign have come from across the political spectrum and a successful recall petition would lead to a by-election later this year, something that is widely predicted.

In an address to Parliament yesterday, during which his voice shook with emotion, Mr Paisley appealed to his constituents to retain confidence in him.

A parliamentary watchdog has recommended that he be suspended from the House of Commons for 30 sitting days for failing to register the luxury holidays.

Mr Paisley said it was with "profound personal regret and deep personal embarrassment" that he had to make a statement as he acknowledged he had failed to declare and register the trips.

But he denied he had any "ulterior motive for that genuine mistake" in 2013, adding that he accepted his "total failure".

Mr Paisley added: "I say sorry and apologise for the failings that were identified in the Standards Committee report."

He said his constituents have given him "unwavering support" since electing him as MP in 2010, adding: "I hope they will continue to have that confidence in me in the future."

The Commons Standards Committee said Mr Paisley was guilty of "serious misconduct" and his actions "were of a nature to bring the House of Commons into disrepute".

The DUP MP expressed disappointment that he could not persuade the committee about the strength of his arguments and mitigation, including on paid advocacy.

Mr Paisley said he accepted the report but regretted the sanctions.

He continued: "I take my duties as a Member of Parliament seriously.

"I believe I conduct myself with colleagues with integrity, with openness, and that is why I have such remorse about the matter as I believe it goes against the grain of who I am - especially how it is portrayed."

Mr Paisley said he believed in "politics and politicians" who could admit "human frailty, can apologise, can mean it and can move on - because that's what real life is all about".

He stated: "It's often said it's how we respond to these challenges in our lives that defines who and what we are, and defines our character and demonstrates to us where the true source of our personal strength rests. The eighth-century prophet Isaiah said: 'You were angry with me, that anger has turned away, you comfort me.'

"I hope to learn that lesson."

Mr Paisley's potential suspension will start in September if MPs approve it next week.

Members who are suspended from the Commons for more than 10 days are open to a recall petition.

A by-election would be triggered if 10% of Mr Paisley's North Antrim constituency sign that petition.

The suspension will also mean Mrs May will lose one of the 10 DUP MPs propping up her minority government during a period that could see a number of crucial Brexit votes.

The Commons Standards Committee report said the cost of the hospitality during Mr Paisley's Sri Lankan holidays may have been "significantly more" than his £50,000 estimate.

The holidays included business class air travel, accommodation at first-class hotels and more for him and his wider family.

The threshold for registering such hospitality in 2013 was around £660.

In March 2014, Mr Paisley lobbied against a proposed United Nations resolution to investigate human rights abuse allegations aimed at Sri Lanka, with the committee noting that the financial benefits were not declared in his letter to then Prime Minister David Cameron.